Calculating machine



June 30, 1942. A. F. POTT I 2 3;3 3-

- CALCULATING MACHINE Original Filad Sept. 23, 1931 15 Sheets-Sheet l Q. Q: Q I. 5 y

A A. F. POTT- 2,288,323

CALCULATING MACHINE June 30, 1942.

Original Filed Sept. 23, 1931 15 Sheets-Sheet 2 W! it ill? I June 30,1942. A. F. Pow v 2,288,323

CALCULATING MACHINE Original Filed Sept. 2:5, 19:51 15 Sheets-Sheet 5 June 1942- A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 4 June 30, 1942. A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 5 June 30, 1942. A. F. POTT CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 6 June 30, 1942. A. F. POTT CALCULATING MACHINE 15 Sheets-Sheet 7.

Original Filed Sept. 23, 1931 maveN'T'o R June 30, 1942. A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 8 June 30, 1942. A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 9 June 30, 1942. A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet l0 June so, 1942. I A, F, pm 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet l1 June so, 1942. A. F POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 12 June 30, 1942. A. F. Pofi CALCULATING MACHINE Original Filed Sept. 23, 1931 15 Sheets-Sheet 13 June 30, 1942. A. F. POTT 2,288,323

CALCULATING MACHINE Original Filed Sept. 23, 1931 '15 Sheets-Sheet 14 June 30, 1942. A, F, po'r'r CALCULATING mourns 15 Sheets-Sheet 15 Original Filed Sept. 23; 1931 parts of the drive Patented une 30, 1942 UNIT D (STATE CALCULATING MACHINE August Friedrich Pott,

assignor to Merced Aktiengesellschaft, Germany Zellt-Mehlis, Germany,

BuromaschinemWerke Zella-Mehlis, 'Ihuringia,

Original application September 23, 1931, Serial No. 564,643. Divided and this application June 10, 1937, Serial No. 147,589.

I her 2, 1930 In Germany Octo- 4 Claims. (01. 235-452) My invention relates to calculating mechanism and more particularly to improvements in multiplying mechanism for calculating machines of the Mercedes Euclid type as exemplified in my Patent No. 2,143,741 of which the present application is -a division.

The primary object of my invention is to equip a calculating'machine of this type for the performance of multiplication in either direction of movement of the accumulator carriage and to, provide efficient controls of simplified construction for conditioning the machine for operation as abovespecified.

Anotherobject is to equip a calculating machine with practical and efficient mechanism for performing of negative multiplication in either direction of movement of said carriage.

Still another object is to provide in a calculating machine including a revolutions counter an efficient correction mechanism by means of which the revolutions counter may be reversed under control of a correction key or disabled by said key at will.

Still another object is to provide mechanism for the purposes above specified which may be readily incorporated in machines of the type previously identified without altering the over' all standardized dimensions of such machines.

Other. and subordinate objects are also comprehended bymy' invention all ofwhich together with the exact nature of my improvements will be readily understood when the following description and claims are read with reference to the drawings accompanying and forming part .of this specification.

In said drawings:

Figure l is a view in perspective of a Mercedes Euclid calculating machine equipped according to my invention, .the cover plate of the machine being removed and parts broken away to disclose the interior mechanism,

Fig. 2 is a similar view with the carriage of the machine tilted upwardly to illustrate the under side of the mechanism thereon.

Fig-3 is a view in perspective looking at the rear side of the machine,

Fig. 4 is a detail view partly in transverse section and partly in side elevation of the main drive shaft of the machine, clutcheson said shaft, parts of the carriage reverse mechanism, to the revolutions counter, and parts of the drive to the differential actuators,

Fig. 5 is a front elevation of parts shown in Fig. 4,

and subtract keys, 3.

Fig. 6 is adetail plan view of parts of reverse gearing for the revolutions counter,

Fig. '7 is a view in longitudinal section of parts of said reverse gearing,

Fig. 7a is a plan view of said parts of said reverse gearing with said parts separated for clearness of illustration,

Fig. 8 is a fragmentary plan view of coupling mechanism between the value setting up mechanism and the accumulator,

Fig. 9 is a view in perspective, with the parts disassembled, of the main drive shaft and the clutches thereon,

Fig. 10 is a perspective View of parts of :the carriage reverse mechanism and automatic actuator conditioning mechanism the parts being disassembled for clearness of illustration,

Fig. 11 is a view in perspective of part of the motor, motor controlling mechanism, the actuator clutch, the clutch control shaft, means for operating said shaft, the actuators, the "add dd-subtract conditioning mechanism for said actuators, cycle controlling or repeat mechanism and parts of the automatic actuator. conditioning mechanism and overdraft conditioning mechanism, 4

Fig. 12 is a view in top plan of the special control keys and a key mounting frame therefor.

Fig-13 is a view in perspective of the special control keys and parts directly associated therewith, the keys and parts being separated for clearness of illustration,

Fig; 14 is a similar view of the multiplication key, the plus and minus or positive and-negative multiplication keys, parts of the actuatorcondi- -tioning mechanism and connections between said keys and mechanism,

Fig. 15 is a view in perspective of the overdraft mechanism, overdraft conditioning mechanism, disabling mechanism, parts of the control mechanism for the carriage, the clutch control shaft, the clutch control flap, and parts of the multiplication mechanism proper,

Fig. 16 is a view inside elevation of an overdraft slide forr'nlng part of the overdraft mechanism,

, Fig. 1'7 is a fragmentary perspective view of the clutch control shaft and parts directly associated therewith.

Fig. 18 is a view in perspective of parts of thegear conditioning mechanism for the carriage reverse gearing,

Fig. 19 is a group view in perspective of a plurality of levers forming part of the gear conditiom'ng mechanism for the carriage reverse\ shown separated from carriage and subjacent parts 'taken on the line -20 of Fig. 1 looking in the direction indicated by the arrows,

Fig. 21 is a view in side elevation of a multi-- plier lever,

. Fig. 22 is a view 'inperspective of the dinerential actuators, the value setting up mechanism, the coupling mechanism between said valve selec'ting mechanism and the accumulator, parts of the drive to said actuators, one of the key locking bars, the key locking bail, a conditioning crank and a conditioning bar forming part of the revolutions counter conditioning means, and a shaft and crank for setting said bar,

Figs. 23 to 27 are views in side elevation, of a counter conditioning crank and conditioning bar together with other parts associated therewith and comprising part of counter conditioning mechanism, the parts being shown in the different positions they assume under different conditions presently referred to in detail,

Fig. 28 is a fragmentary view in front elevation of the revolutions counter, the drive shaft therefor and a detent for said shaft,

Fig. 29 is a diagrammatic view of said shaft,-

Fig. 30 is a fragmentary plan view of the revolutions counter with the parts on ,an enlarged scale to more clearly illustrate their relation,

Fig. 31 is a detail view in longitudinal section of the right hand end of the revolutions counter drive shaft, a transfer blade. mounted therein and means for mounting said blade, the parts being shown disassembled,

'Fig. 32 is a view in transverse section of the carriage and subjacent parts taken on the line 32-32 of Fig. 1 looking in the direction indicated by the arrows,

Fig. 33 is a detail view of overthrow preventing means for the revolutions counter.

GENERAL Oncamzarron The frame F (Figs. 1 to 3) supports at the rear thereof the usual carriage C mounted thereon suitably pivoted for tilting movement for a purpose well understood and denominationally movable, for step by step advance to the right and retraction to the left in the rear of the usual denominational rows of value keys K. The carriage C supports an accumulator A (Fig. 1) and a revolutions counter RC (Fig.1) adapted to be read through suitable sight openings S in thecoverplate 1 of said carriage. The machine iso e ated by means of a motor I s. 3, 1

and a m'aindrive shafti' (Figs. 3 to 5, 9, 11) to tor is geared by a worm 3 and a worm wheel 4 fast on said armature tively. I

Upon opposite sides of the value keys K (Figs. 1, 2) are two groups 'of special control keys, one including. addition and subtraction keys I and i 8 designated "Add" and Sub (Figs. 1, 2, 11), re-

spectively, a keyboard resetting key 9 designated R f, an accumulator resetting key ll designated and driveshafts respecspectively, also a correction key 2|, a division key I! and a division correction key I! (Figs. 1, 2, 12). -0nly the automatic multiplication lever II, the minus multiplication key 22, the plus and minus keys I! and II, and the carriage advancing and retracting keys I! and I: are material to'the present invention. The other keys and lever 12 have been referred to merely to com-. plete identification of the particular type of machine disclosed.

Value setting up mechanism prises denominational series of differentially movable gears R to R '(Figs. 22) one series for each denominational row of value keys K, the gears of each series'being splined upon a suitably journaled shaft I54 for setting along the same into diiferent positions by their related value keys K. Driving gears, as atl55 (Figs. 20, 22), one of which is fast on each shaft I54, operate the accumulator A through the medium of coupling mechanism presently referred to in detail.

The value keys K are locked depressed by key locking bars, as at I18 (Fig. 22) one for each row of keys, tensioned for movement to locking position by springs, as at "8a, and movable under depression of one value key of a related row to release another depressed key of said row all as disclosed in Patent No. 1,935,858 supra. As will be understood a value set up is retained in the value setting up mechanism by such locking of the value keys.

' which'the armature shaft 2 (Fig. 11) of said mo- (Figs. 1, 2, 12, 13), plus and minus, or positive The diflerential mechanism The Mercedes Euclid calculating machine, is an adding mechanism equipped with a well known type of diiferential mechanism conditionable under control of the Addand Sub keys I and lto add'in the accumulator A either the actual or the complements of the values set up in the value setting up mechanism. For the details of-the differential mechanism attention is directed to U. S. Patent No. 1,011,617.

Briefly described said mechanism comprises a series of ten laterally spaced actuator racks, designated as a unit R in Fig. 22, reciprocable transversely of the machine and with which the before mentioned gears R to R mesh in their different set positions. Said racks are conditionable for movement in different degree on their for- -ward stroke to rotate said gearsin accordance with either the actual or complemental values of the depressed value keys K. Said racks R' are conditioned by means of a locking bolt I49 (Figs. 11, 14, 22) slidably mounted for setting in opposite directionsto alternately lock the outside racks of said series against movement in, addition and subtraction respectively, said bolt projecting through said outside racks as 'will be understood. The locking bolt forms part-of actuator conditioning mechanism tobe described.

' The accumulator The accumulator A comprises the usual dey and negative multiplication keys I! and II, re-

4'06 althoughi thenumber QfI' SIIChf wheels and .20, 22, 32)... are operated by transfer-cams 254 on atens olutions counter RC as follows.

shafts may bewaried: as ,desired. Fast on the shafts. 8 aregears; l09a -(Figsa20, 22, 32) driven 'by-thebefore; mentioned coupling mechanism to @be, described. The usual-knobs 1091). (Figs. 1, 3, on said shafts l 0.8 are. provided for manually setting upyalues in thevalue, Wheels I09 at will. The accumulatoiuAds equipped with transfer mechanism; including tens carrying members its (Figs- 2,20, 22, 32 conditioned for transferring operations preparatory members I090 and conditioning resetting or looking flap I09e (Figs. The tens carrying members 169 The revolutions counter Loosely mounted onth e eight. right hand shafts I08, in the rear of the eight right hand value wheels I09 and related thereto, are eight revolutions counter value wheels H0 (Figs. 1, 28, 30, 32) each having delineated on its periphery the symbols 0 to 9 reverselyarranged relative to the symbols on their related value wheels I09. The counter value whe'ls 0 are rotated step by step through themedium of subjacent star wheels 359 (Figs. 20,30, 32) related to said wheels respectively, and each having fast thereon a gear 364 (Figs. 28, 30, 32) meshing with a gear 366 fasten the related value wheel I 10 (Figs. 30, 32).' Each gear 364, except that related to thevalue wheel H0 of highest denomination, is provided with a transfer tooth 369 (Figs. 30, 32)

adapted upon rotation of the value wheel 1 l0 related to said gear" from 9 to 0, or, vice versa, to engage a transfer gear 310 (Figs. 30,- 32) on the value wheel of next higher denomination and to impart a half step of rotation thereto.

(Figs. 7a, 28, 29, 31, 32) suitably journaled in the main frame F transversely-thereof to extend lengthwise of the revolutions counter RC. The

tens carrying shaft 306 is equippedto drive and complete the transferring. operations in the revv Adjacent the right hand end of said shaft 306 is a pair of opposed transfer blades 340 and 34! (Figs. 28, 29,

3'1) spaced apart transversely of said shaft and inclined lengthwise thereof. The transport pieces 340 and .341 (Fig. 28) are so arrangedthat in successive denominational positions of the carriage C said blades, duringeach revolution of said shaft in opposite directions, impart a complete step of movement to successive star wheels 359 in opposite directions, respectively, and consequently tothe counter value wheels H0. It will of course be understood that the revolutions counter operates in opposite directions in additive and subtractive operations respectively. Extending along said shaft 306 transversely thereof, from said blades 340, 3 are equidistantly spaced rib-like transport pieces 329 to 339 (Fig. 28) arranged in like formation so that ends thereof form oppositely related spirals around said shaft 306 as shown diagrammatically in Fig. 29. One

Below -the star gears 359 is a tens carrying shaft 306 entered into herein.

end of .the transfer, pi ces 30 333 and the pieces -3 o 8;.; e-. 28 ..e te-efi ct e i -O direction of, rotationo id shaft 3.06, to .irnpart;a f step fm rem t es yrvheel 3592 tion of movement o f said.,-shaft 306. to similarly operate said star ,wheels .3 5.9 and hence related value wheels I l0 in; the: opposite direction. The pieces 340, 341 are yieldingly mounted in the shaft 306 to normally project therefrom and so that upon continued, rotation of. said shaft. in

either direction the trailing piece will ,bedea right angle to the slot 343. An angled end 353 on said detent bar seating in a socket 354 in. the bottom of the slot 355 holds said bar against endwise displacement. A tension spring 349 (Fig. 31) disposed in a bore 348 in said shaft 306 and having its opposite 'ends connected to a plug 350 in said bore and to said detent bar 352 respectively retains the latter against the bottom of the slot 355 and thereby holds the piece in-proje'cted position. Each piece 349,341 is notched as at 345 and formed with a lug 344 seating in a socket'346 for a purpose immaterial tothe present'invention and-which thereforeneed not be I As will be understood, the pieces 340, 34!, and the transfer pieces 329 to 339 are spaced around the shaft .306 so as to permit in the normal position of said shaft, movement of the star wheels 359 along said shaft by the carriage C. The shaft 306 is yieldingly On the main drive shaft 5 is a carriagedriving clutch 262 of the single revolution type (Figsmi and 9) comprising a pair. of opposed; circular housing members262a-262b (Fig. 9), a ratchet sleeve 260 fast on said shaft 5, and a clutch trip pawl 26! pivotally mounted between said members 262a, 2621) for engagement with said ratchet sleeve and tensioned by a suitably connected spring 26: to engage said, sleeve.- Theclutch 262 is geared to the usual carriage propelling rack [6a. (Figs. 20 and 32) as follows. Fast on the housing member 262a-(Figs. 4 and -9) isa carriage driving gear 262e. Suitablyjournaledpn the main frame F is a carriage driving sleeve 262d (Fig. 10) having fast on one end thereofa pin gear 262e meshingwith the carriage rack l6a. A detent lever 262 tensioned by a suitably arranged spring 2629 (Fig. 10) for cooperation with said pin gear 262e to urge the same in normal position and. prevent overthrow thereof. (A pair of carriage reversing gears 239, 240 (Figs. 4, 10) are rotatably mounted on said sleeve 262d said gears constituting right: and left handdriving or carriage advancing and retracting gears respectively. The carriage advancing gear 239 meshes with the carriage driving gear 262a. The retracting gear 248 is driven by saidgear 262a oppositely to the advancing gear 239 through the medium of an idler gear 248a (Fig.

4). gears 239,. 248 are adapted to be alternately coupled to said sleeve 282d (Fig. by means of a draw key 289 having a key lug 268 therein projecting through a key way 268a in said sleeve andendwise settable in opposite directions .to

The carriage advancing and retracting.

engage said lug 268 with key ways 239a and 2481; provided in said gears 239and 248, respectively, whereby in the opposite settings of said key 269 the described reverse gearing is conditioned for advance to the right or retraction to the left of the carriage C respectively,

The draw key 289 is settable to condition the I described carriage reverse gearing for advanceunimportant to the present invention and need not be described. The levers 236 and 231 (Figs. 3, 18,19) are recessed as .at 235 and 231a respectively for a purpose which will be later pointed out in detail. The lever 238 is pivotally connectedat its lower end to a rod 281a which is pivotally connected to a draw key setting lever 281 (Figs. 3, 10, 18) operatively connected to said key 269. The draw key 269 is normally set to condition the described carriage reverse gearing for retraction to the left of the carriage C by means of a rocking .bell crank 24I (Figs. '3, '18) "suitably mounted on the frame F and 'operatively connected to the intermediate lever 231, as at 265, and a suitably connected spring 218 urging said bell crank I and lever 231 in-the proper direction (Fig. 3). retracting-keys I4 and I3 are operatively related to said gear conditioning unit by means of a pair of bell cranks I31: and I 4a (Figs. 3, 15, 18) adapted to swing said unit in opposite'directions, respectively, a pair of links Ilb, ,I3b operativ'ely connect said keys I4 and I3 to the bell cranks Ila and I3a respectively. Suitably connected springs I4e and I (Figs. 3 15,-18)'tension said bel1 cranks. Ila. and I3a, respectively, against operation by said keys and said keys against depression. The condition of the carriage reverse gearing under'depression of 'the keys I4 and I3 is reversed inthe left and right hand 'limits'of spectively, mounted on said carriage and coacting with the before mentioned bell crank 24I to rock thedescribed gear conditioning unit in opposite directions respectively.

Under depression of the carriage advancing and retracting keys I4 and I3 the bellcranks Ill:

The carriage advancing andbeforementioned ratchet sleeve 258.

member I82a is operatively connected to,a suitdepression of the carriage advancing key I4 by -means of coacting parts 681), 236a (Fig. 1'1) on the crank 86a and lever 238, respectively; so that the carriage C continues to advance to the right until said key is returned in the limit of right hand movement of said carriage by coaction of the left hand tappet 263. (Figs. 3, 18) and bell crank 2 to swing the gear conditioning unit in a direction to condition the carriage reverse gearing for retraction of said carriage. Alsoun- .der depression of the retracting key I3 similar results are obtained as regards retraction to the left of 'said carriage C and return of key I3. The spring 238a and the slot 238!) in the lever 238 (Figs. 3, 18) together-with the other features set forth in this paragraph form per se, no part ofthe present invention being subject matterof my co-pending application Serial No. 141,587, filed 'of even date herewith. Therefore further description thereof is thought to be unnecessary to a proper understanding of the instant invention.

Drive to accumulator On the main dribe shaft 5, alongside the carriage clutch 282 and identical in construction therewith is an actuator di'iving clutch I82 comprising housing members 182a, I821), (Figs. 4, 9) a clutch trip pawl 259 therebetween and a spring 242 tensioning said pawl for engagement with the Clutch ably journaled driving shaft 258 (Figs. 4,5) by means of intermeshing gears 248, 249 fast on saidmember and shaft respectively. The driving shaft 258 is operatively connected to the differ- ,ential actuators R (Fig. 22) to impart a reciprocatory cycle of operation thereto during each.

bevel gears :52, 2 53 (Figs.4 and 8) fast on said driving and transfer shaft respectively.

As previously stated the driving gears I55 (Figs. 28, 22) of thevalue setting up mechanism operate the accumulator A by, means of coupl fg mechanism. Said. coupling" mechanism Fest shown in Fig. 22 comprises a series of denominational gears I55a rotatably mounted in a coupling 3 gear frame I55b which in. suitablemanrier is rothrough operating connections comprising a pin and I3a engage'a crank member 66a (Fig. 17)

fast updn a transverse 'clutch' control rock shaft 88 and rock the latter, clockwise as viewedin Figs. 11, 15, and 17, to effect engagement of the carriage clutch 282 in a manner to be'descr'ibed. It may be mentioned that the clutch control shaft 68 is interlocked with the lever 236 of the described gear conditioning u'nit under sustainedtatably-mounted in the main frame F to intermittently mesh said gears|55a with gears I55 and gears 189a on the shafts I88 (Figs. 20, 22). Intermittent rotation is imparted to the frame I55bby the transfer shaft I 3I (Figs. ,8, 20)

gear I55c (Fig. 8) fast on saidtransfer shaftand meshing-with a suitably mounted two part Maltese cross I55d and a gear train extending between said Maltese cross I55d and the shaft I55b and designated generally by the.reference character I55e (Figs. 8, 22). For the present purpo'ses it is sufficient to explain that-the described coupling mechanism serves for coupling the value setting up mechanism to appropriate gears I890 during each forward stroke of the actuators R and uncoupling-the same during retum'strokes of saidactuators.

Drive to revolutions counter The revolutions counter driving shaft 306 (Fig. 28) is driven in opposite directions in addition and subtraction by the transfer shaft I3I through the medium of a reverse gearing as follows. Fast on said shafts 306 and I3I are gears 324 and 3I6 respectively (Figs. 4, 5, 8, 28). A sleeve I60 (Fig. 6) similar to sleeve 262d before described, is suitably journaled on the main frame F said sleeve having a gear 3I5 fast thereon meshing with the gear 3I6. A pair of forward and reverse driving gears I59, 202 (Figs. 5, 6, 7a) for addition and subtraction, respectively, are freely mounted on said sleeve I60. The forward driving or addition gear I59 is driven by the gear 324 through integral twin gears 325, 328, (Fig. 7a), the gear 325 meshing with gear 324 and the gear 328 meshing with gear I59 whereby the shaft 306 and value wheels IIO are .driven in the directions indicated by the arrows in Fig. 28. The reverse driving or subtraction gear 202 (Figs. 5, 6) meshes directly with gear 324 whereby said shaft 306 and value wheels IIO are driven in directions opposite to those indicated by said arrows (Fig. 28) A draw k'ey I51 (Figs. 6, '1), similar to draw key 269, is settable in said sleeve I60 in opposite directions to alternatively couple said gears I59, 202 to said sleeve by means of a key lug I58 on said key, a key way I60a in said sleeve and key ways 305, 304 (Fig. 6) in said gears I59, 202 respectively. The draw key I51 is also settable into an intermediate position represented in Fig. 7 in which both gears I59, 202 are uncoupled from said sleeve I60 and the revolutions counter RC thereby disabled. The setting of the draw key I51 is accomplished by means which will presently be described under appropriate headings.

Add and subtract conditioning means- At this point the add and subtract conditioning mechanism which forms in part a part of the multiplication mechanism will be briefly described.

The basic element of said add and subtract conditioning mechanism is a transverse conditioning rock shaft I48, at the rear of the machine (Fig. 11), upon one end of which an actuator conditioning crank I41. is secured, intermediate its ends, with one end operatively connected, as at I41a to the before mentioned locking bolt I49 so that upon rocking movement of said shaft I48 in opposite directions said bolt will be set to condition the actuators R for addition and subtractions respectively. The crank I41 has a lateral stud 244 (Figs. 11, 14) on its opposite end the function of which will presently appear. Between the Add and Sub keys 1 and 8 and shaft I48 are operating connections designated I48a, I482), I480 (Fig..11), operated by studs 1b, Bb of the key levers 1a, 8a of the add .sub

' keys 1 and 8, respectively, whereby depression of said keys 1 and 8 (Fig. 11) efiectsrocking of said shaft I48 in opposite directions said connections permitting independent rocking of said shaft. Since the details of said operating connections are immaterial, to the instant invention they need not be described herein.

As an incident to such rocking of the conditioning shaft I48 to condition the'actuators R for addition or subtraction the revolutions "counter RC is similarly conditionedby means of a verticallydisposed conditioning crank I52 fast intermediate its ends on said shaft I48 (Figs. 11, 14, 22, 23-27). A draw key setting bell crank I53a. (Figs. 6, 22), pivoted at a fixed point I56 .correction shaft I 15.

is ,'-'pivotally connected with a bar I53 in such manner as to accommodate vertical movement of the latter. The crank I52 (Figs. 22-2'7) has formed therein a pair of upper and lower substantially triangular recesses 3I0, 3| 0a, respectively, and notches 200, 200a are formed at the apexes of said recesses 3I0, 3I0a as shown in Figs. 22 to 27. The bar I53 is provided with upper and lower studs 20I, 294, respectively, arranged thereon so that upon vertical movement of said bar I53 in opposite directions said studs MI, 294 may be engaged with said upper and lower notches respectively. Under normal adding and subtracting conditions the bar I53 is held elevated by a crank 300 (Figs. 1, 2, 13, 22-27) fast on a transverse correction rock shaft I15 and having a slot and pin connection 302, 30I (Figs. 22-27) to said bar. In this position of the parts the upper stud 20I of said bar I53 engages the upper notch 200 of said crank I52 whereby upon movement of the conditioning rock shaft I48 in opposite directions the draw key I51 (Figs. 6, '7, 7a) is set in opposite directions to condition the counter reverse gearing and hence the counter RC for addition aid subtraction.

It may be explained at this point that in correction operations the bar I53 is moved or set vertically into an intermediate position by the correction shaft I15 (Figs. 22-2'7) and crank 300 in which position a slot 303 in said bar I53 coacts with one end of the shaft I48 to cam said bar endwise to effect a setting of the draw key I51 into its intermediate position previously referred, to whereby the revolutions counter RC is disabled as previously explained. The triangular recesses 3| 0, 3I0a coact with the studs 20I, 294 to cam the same into the notches 200, 200a when bar I53 is in its upper or lower position.

Returning now to the carriage C and actuator clutches 262, I82 (Figs. 4, 9, 11), said clutches are controlled by means of a clutch tripping dog I81 (Figs. 4, 11) fast on the previously identified clutch control shaft 66 and together with said shaft normally occupying an intermediate position in which both trip pawls 26H 259 (Fig. 9) are tripped and said clutches thereby disengaged. The clutch control shaft 66 and clutch tripping dog I81 as will be understood are adapted to be rocked in opposite directions into carriage and actuator clutch engaging positions respectively, to effect alternate engagement of said clutches 262, I82. A pair of segmental cams 262h, I820 (Fig. 9) on the clutches 262, I82, respectively, block movement of the clutch tripping dog 'I81'to said positions until whichever clutch is engaged has completed a full revolution.

The clutch control shaft 651s rocked in one direction under controlof theadd and sub" keys 1 and 8 through the medium of a key locking bail I16 (Figs. 11, 22) swingable forwardly and rearwardly on the before mentioned The key locking bail in its forward movement coacts with arms I11 (Fig. 22) on the before mentionedkey locking bars I18 and blocks movement of the latter to key releasing position. Also in'its forward movement said bail I16 coacts with an arm I19 (Fig. 11) on a yoke I80 ,pivotally mounted ona transverse shaft HM and swings said yoke forwardly against the tension of a suitably connected spring IBM. The yoke I is operatively connected by a link I83 to a clutch controlrocker 245 (Fig. 

